1. Field of the Invention
The present invention relates to an electronic circuit device and, more specifically, relates to an electronic circuit device capable of dissipating heat generated by an electronic component included in the electronic circuit device.
2. Description of the Related Art
In the past, multilayer substrates for embedding electronic components so as to obtain highly dense and highly integrated electronic components, such as semiconductor chips (e.g., PCT Japanese Translation Patent Publication No. 7-107954).
A method for producing a known multilayer substrate with embedded electronic components will be briefly described in sequence below with reference to FIGS. 1 and 2.
FIG. 1A illustrates a substrate 1. On one of the surfaces (upper surface in the drawings) of the substrate 1, wiring is provided by copper foil 2 so as to form a circuit.
As illustrated in FIG. 1B, a semiconductor chip 3 with its active surface (device surface) facing toward the substrate 1 is disposed on the substrate 1. Bumps 4 are formed on electrodes (not shown in the drawings) of the semiconductor chip 3. The semiconductor chip 3 is fixed to the substrate 1 by a bonding member, such as solder or conductive paste, and is electrically connected to the circuit via the copper foil 2. A sealing resin 5 is interposed between the semiconductor chip 3 and the substrate 1 so as to increase the connection strength between the substrate 1 and the semiconductor chip 3 and to prevent intrusion of moisture.
Next, as illustrated in FIG. 1C, the upper surface of the substrate 1 with the semiconductor chip 3 is flattened by applying a resin 6. On the surface of the substrate 1 flattened by the resin 6, wiring is provided by the copper foil 7, a circuit is formed, and a substrate 8 is stacked.
As illustrated in FIG. 2, through-holes are formed in the substrate 1 and the substrate 8 from the upper surface of the substrate 8 to the lower surface of the substrate 1 in positions where the semiconductor chip is not disposed. By plating each of the through-holes entirely with a conductive material, such as copper, through-holes 9 are formed. Circuits composed of copper foil 10 are formed on the upper surface of the substrate 8 and are electrically connected to the through-holes 9. Other circuits composed of copper foil 11 are formed on the lower surface of the substrate 1 and are electrically connected to the through-holes 9. In this way, a multilayer substrate 21 is produced.
As described above, the known multilayer substrate 21 is produced by including the semiconductor chip 3 in the multilayer substrate 21 as part of the multilayer substrate 21.
Recently, in the technological field of mobile phones and home information appliances, there has been a demand for reduction in size and weight and improvement in advanced functions. For this reason, highly efficient electronic devices have been in demand for mobile phones and home information appliances. However, many of these highly efficient electronic devices generate high-temperature heat.